<!doctype html> 
<html> 
<head> 
    <meta charset="utf-8"> 
    <title></title> 
</head>
<body>
<script type="text/javascript">

//Array String Number Boolean Function Object
//null undefined Date NaN RegExp Arguments
//toString
//var a = new RegExp('/b+');
//alert(a.toString());

//function a(){
	// this = xxx
	// return this;
//}

//alert(null.constructor)
//console.log(Object.prototype.toString.call(null));
//[object Number]
//[object HTMLBodyElement]
//[object String]
//[object Null]
//[object Boolean]
//[object Date]


</script>
</body>
</html>